Sorry, I should have been more clear.
The water in my tank is now, after just testing, 6.6 Ph and the Kh is 5. The water I use to fill the tank -- R/O from my LFS -- is Ph 7.0 and Kh 0 / Gh 0 or 1.
My test kit is aquarium pharma.
So, I do really wonder why my Kh has risen from 0 to 5. I understand why my Ph has dropped -- that's because I added CO2 this weekend. But what would give a Kh reading higher than 0? And that makes my tank have ~38mg/l of CO2. That can't be right, can it? DIY CO2 ion 29G?
Here's everything in my tank:
Fish, plants, two pieces of malaysian driftwood, some tetra black water extract, some flourish, and eco complete. Thats all, no carbon.
I guess I don't need to add any r/o right, as I'm getting hardness from somewhere, but I'd sure like this to make sense.
--> .26 Liter light bulb retrofitted to be a tank <--
--> 5000W of incandesent lighting placed 37 yards away <--
--> Direct pipeline from Rio Negro filtered through a carbon infused peat moss tea<--
--> DIY CO2 (hired help for mouth to straw to tank application) <--